This invention relates to the field of tools for mechanical work. More particularly, an automatically sized one-handed locking plier is presented.
Locking pliers have been sold in their standard form for decades with little significant improvements. While the pliers perform wonderfully and are a staple in every toolbox around the world, certain improvements would make the locking pliers even more useful. Locking pliers differ from ordinary pliers in that they contain a mechanism to lock the jaws of the pliers onto the work piece. Many different types of locking pliers have been produced, and they are commonly known in the trade as Vise-Grips.RTM. or simply “locking pliers”.
Some of the problems with locking pliers include the fact that they are tedious in use, since iterative screw adjustments must be made to size the jaws to the part.
Pliers that can be easily operated with one hand and that automatically size the jaws to the part, but still provide the quality and clamping force of the standard locking pliers, would provide an advancement in the ease of use and utility of the pliers.
Examples of useful locking plier tools are found in various United States patents of general interest in the field.
One good example of a locking plier tool is found in the 2000 United States patent issued to Warheit, U.S. Pat. No. 6,095,019. Warheit discloses the typical locking plier tool used to clamp onto a work piece. The Warheit device has a thumb actuated control member which facilities work piece pressure adjustment and tool release by one hand. The typical locking pliers, as shown in the patent issued to Warheit and other U.S. patents, include an upper jaw that is permanently attached to an elongated body. A lower jaw is pivotably attached to the locking pliers as well as a lower handle tightening mechanism. A pivoting lever normally connects the upper body and lower tightening mechanism. The pliers are usually tightened for work piece sizing and for grip strength by a thumbscrew mechanism, generally found at the end of the upper body handle.
Several problems have been encountered in the use of previous tools and improvements could prove beneficial. One such problem is that while the tools must be sized to fit the work piece, the sizing is usually done by a thumbscrew mechanism that requires both hands to operate the mechanism. One hand is needed to hold the locking pliers onto the work piece while the other hand is needed to turn the thumbscrew adjustment. It is a primary object of this invention to provide a locking plier type of hand tool that automatically sizes the jaws of the locking pliers onto the work piece.
Another problem with the locking pliers heretofore known in the art is that the sizing of the pliers onto the work piece has a direct correlation to the hand pressure or gripping pressure used to lock the pliers onto the piece. Once the pliers have been sized approximately, a further manipulation of the adjusting thumbscrew would be necessary to adjust the handle grip strength. It is another object of this invention to provide a locking plier that not only automatically sizes the jaws to the workpiece, but also has an adjustment screw, operable by the same hand that holds the pliers, for adjusting the handgrip strength to a set handgrip for each workpiece.
Another major drawback in the use of ordinary locking pliers is that the handgrip strength tensioning mechanism and the sizing mechanism require both hands of the mechanic. Since both hands are needed to attach and tighten the pliers to the workpiece, the task of adjusting the locking pliers is both cumbersome and time consuming. It is a still further object of this invention to provide a locking pliers wherein the use of the pliers is conveniently and quickly accomplished so that the workman uses little or no time when changing from one work piece to another.
A final aspect of this invention allows the locking plier to remain loosely gripped around the work piece when the pliers have been released into their open position. This is a particularly useful feature of the locking plier mechanism of the instant invention since it allows the workman to remove the wrench, with one hand, at the workman's convenience. This feature eliminates the wrench falling on the workman if he is an awkward position. Further in connection with this capability, another advantage of the invention is that releasing the pliers can be accomplished with exertion of a relatively light force, even when the pliers are set to a high gripping or clamping force, as the required release force is not a function of the gripping force. Thus, a further object of the invention is the capability to more easily release the pliers, yet still provide a loose gripping force for holding the pliers on a work piece.
Other and further objects of this invention will become obvious upon reading the below described specification.